In the related art, there has been known a periphery monitoring device which captures an image of a situation around a vehicle by an imaging unit (camera) mounted in the vehicle and displays a captured image on a display device disposed in the vicinity of a driver's seat, thereby making it easy for a driver to recognize the situation around the vehicle. Such a periphery monitoring device may display a trajectory prediction line on the screen of a display device in order to make it easy to recognize, for example, a positional relationship between an own vehicle and a surrounding object or an empty space. In addition, in a towing vehicle having a towing device, the periphery monitoring device may display a trajectory prediction line toward a towed vehicle in order to support an approaching operation to the towed vehicle during connection to the towed vehicle. In addition, in such a type of displaying a trajectory prediction line, the trajectory prediction line may be displayed at a position corresponding to the height of the towing device (hitch) which actually approaches the towed vehicle. See, for example, JP 4739569 B (Reference 1).
In the related art, the trajectory prediction line which is a graphic image different from a camera image is superimposed on a two-dimensional camera image having a depth in a state where height information is applied thereto. Therefore, it may be difficult to determine whether or not the trajectory prediction line is a line that actually has the height information only by looking at the displayed trajectory prediction line. In addition, when not recognized as the line having the height information, the superimposed line may appear to be at an unnatural position, which may damage to correct recognition or determination of a driver.
Thus, a need exists for a periphery monitoring device which is not susceptible to the drawback mentioned above.